Welding gun



' March 27, 1945. w. A: WEIGHTMAN 2,372,413

wmmim GUN Original Filed Aug. 1, 1940 2 Sheets-Sheet l INVENTOR 7 l illmm 1 Weifliman,

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A TTORN F V March 27; 1945. w. A. WEIGHTMAN 2,372,413

WELDING GUN Original Filed Aug. 1, 1940 2 Sheets-Sheet 2 INVENTOR ATTORNEY mlliamfl Weigkiman,

Patented Mar. 27, 1945 WELDING GUN William A. Weightman, Philadelphia, Pa., assignor to Edw. G. Budd Manufacturing Company, Philadelphia, Pa., a corporation of Pennsylvania Original application August 1, 1940, Serial No. 349,308. Divided and this application March 3, 1943, Serial No. 477,805

and bottom members 38 and 40 in two separate 11 Claims.

This invention relates to welding apparatus and more particularly to a welding gun for effecting a plurality of spot welds along the length of a beam or like member.

. This application is a division of my co-pending application Serial Number 349,308, filed August 1, 1940.

' An object of the invention is to provide a welding gun structure of substantial rigidity. A further object is to provide a. welding gun adapted for the securing of heavy welds. An object also is to provide a welding gun with a satisfactory floating mounting for the same.

The above and other objects of the invention are effectuated by the apparatus and mechanism detailed in the following description in conjunction with the accompanying drawings. It is expressly understood, however, that the description and drawings are employed for purposes of illustration only and are not designed as a definition of the limits of the invention, reference being had for this purpose to the appended claims.

Referring to the drawings in which like reference characters indicate like parts throughout.

Figure 1 is an enlarged side elevation of a pair of vertical welding guns, one being illustrated in section along its vertical axis: and

Figure 2 is a longitudinal section through one of the welding guns illustrated in Figure 1, the

section being taken axially through the cylinder and at right angles to the plane of the support of the gun.

Referring to Figure 1 and also Figure 2 wherein the general arrangement of the apparatus is shown, there will appear a track 64 having a carriage 32 thereon adapted to operate upon a workpiece 34 such as an extended column or beam, the latter being supported upon the spaced supportarms arranged along the length of the track. Taking into consideration the particular beam to be operated upon as illustrated in conjunction with Figure 2, it will appear that the various component parts of the beam are to be secured together at certain points and preferably at uniformly spaced intervals along their length. For example the center sill or column structure illustrated is composed of top and bottom members 38 and 40 which have been channelled in the manner illustrated by drawing through a suitable draw bench. The top and bottom members 38 and 40 are centrally reinforced by inner reinforcing channel members 42 and 44. Initially before the final assembly of the various component parts of the sill, the reinforcing members 42 and 44 are secured to the top operations involving the effecting of a plurality of welds, the welds being adapted to secure the adjacent channel faces of the reinforcing members 42 and 44 to the respective faces of the adjacent top and bottom channel members 3'8 and 40. Side members 54 also of channel cross section are in a later stage assembled together with top and bottom members and fixed through Welds securing the side members 54 to the top and bottom members 38 and 40 along the portions of one another that are in face to face or lap contact. In a center sill for railway use, for example, the particular channel members re-' ferred to may be rolled from as heavy strip stock as quarter-inch high tensile stainless steel and the individual welds-securing two such members together are, therefore, efiected through a pair of channel members, the total thickness of which may be as great as a half-inch. Thus such spot welds are of unusual size.

In order to support the carriage 32 and the beam 34 in operative relation "with respect to one another, the carriage 32 is adapted to roll upon'rails 64 carried upon transverse ties 66.

The carriage 32 as illustrated in Figure l is generally constructed of spaced side frames 10 connected together across the top thereof by a bridge or top framework member. Each side frame is composed of a lower sill l5 and one or more spaced uprights such as 78 spaced along the length thereof at convenient points. The sill 1B is provided with flanged wheels 80 which in turn roll upon the track 54 and are adapted to maintain the carriage aligned along the track with respect to the beam 34 throughout its operations thereupon as it traverses the beam 34 and track from one end to the other.

To efi'ect the vertical welds 5D and 62 between the channel members 38 and 40 and 54 of the center sill, the welding guns 96 are positioned on the inside of the side members It! of the carriage. Such welding guns are supported from the side members at the top and bottom through identical top and bottom castings 98 and I00. As is illustrated, for example in Figure 1, two welding gunsare supported upon each side of the carriage, one gun B being adapted to efiect welds as indicated at 62 and the other, C, being adapted to effect welds as indicated at 60. Each of the guns is identical but the gun for effecting the welds 62 is inverted with respect to the gun which effects the welds 60. The end support castings 98 and H10 are also reversed with respect to one another as will hereinafter appear.

In order to effect the heavy welds contemplated it isnecessary to apply heavy pressures to the welding electrodes and since the welding electrodes must overhang to a considerable extent to reach into the contour of the channel members of the beam, to be welded, provision must be made to mechanically resist such torsion and other eccentric stresses which would be set up in each welding gun. Accordingly, as will be.

seen in Figure 1, each welding gun is carried upon a pair of spaced heavy guide rods I02 extending between the cast end'supports 90 and I00. As is shown in section in Figure 1 thezlower cast end piece I is provided with-a cylinderbore I04 integral therein and having an axis lying in substantially the same plane asthat common to the axes of the rods I02. slidably arranged upon the rods I02 are welding electrode carrier "guide blocks I06 and I08, the former being provided with a piston rod IIO extending through the lat ter into the rcylinder I04 wherein it is provided with a piston H2. The other block I08 through which the pistonrod IIOpassesisprovided with an integral extension portion II.4-forniing a pis ton headlikewise reciprocating within the cyline der I04.

Theelectrodecarrying blocks I06 and I08 (see Figure 2) are provided with electrode carrying brackets II Iiand Ida-secured tothe blocks through bolts I-ZIJ,-there being provided layers of: insulation I22 and I24 between the brackets and bolts and theirfrespective blocks. The, bracket H6 is provided-with a goose neck at the end thereof: to

support a welding electrode :tip I26 in such a wayasnot to interfere with the flange I 21 of the channel member 54. The lower electrode bracketis provided with an opposed electrode tip I28, the electrode tips I26. and-l28 being adapted toengage the .channelmembers 54 and 38 to ef feota we1dat'thepoint62 (see Fig. 2').

It will be seen that the electrode carrying blocks I06 and I08 are both slidable upon the rods I02 and carry the piston head '4 and the arate are provided. In order to restrict the extent of the separation of the welding electrodes upon the completion of a weld and so as to prevent the electrode tips from separating suflicientlyto come in contact with theiadjacent side walls or flanges, for example the flange I21 of the channel member 54 (see Fig. 2), ashoulder I32 concentric around the piston II4 is-adapted to engage the end of the cylinder bore I04 as at I34, through one or more adjustment collarsJSIj. ,The adjust ent collars are removable since each collar is v composed of two substantially semi-circular parts IIand I31 hinged together as at I38. Thus, downward .(see Fig. 1) or upward (see Fig. 2

movement of the block I08 and its electrode is adjustably limited. Movement of the block I 06 as a result of the pressure of the springs I30 is limited by the adjustable threaded collars I40 arranged upon the extension of the piston rod III), the collars being adapted to abut a"be1l-' shaped end enclosure I42 of the cylinder'I04. It

will readily appear that the collars I36 and I40 are effective to limit the separation of the welding electrodes regardless of whether the welding gun be positioned as illustrated in the right-hand portion of Figure 1, or inverted as in the left-hand portionzof Figure 1, or, for example, as illustrated inFigure 2.

Engagement of the welding electrodes with the work is accomplished by introducing fluid under ,pressure to the space between the pistons II 2 and H4 through the bore I44 extending through the center of the piston rod H0, which bore terminates in a transverse aperture I46 leading into the space between the pistons. Thus, by introducing fluid under pressure through the hollow piston .rod, the piston and piston head may be forced to spread thereby causing the welding electrodes to engage the work under pressure.

Connections to the welding guns 96 are completed through bars 2I6 and 2I8 and flexible jumpers 220- completing connection t the lugs II-Band H8 of each of the welding guns. Each;

of the bus bars 2! 0 and 218 has a horizontal por;

tion connected to the powerv source, an 'intrme diate vertical portion and ahorizontalportion'to which thegun jumpers 2 20 are. connected.

Tho-ugh only a single form of the invention particularlyapplicable to the beam shown, is illustratedand described the invention is not lirn-' ited thereto but may be embodied in various iormsas desired. As various changes in construction and arrangement of parts may be, made. without separating from the spirit of the inven; tion as will be apparent to those skilled in the art, reference will behad to the appended claims for a definition of'the limits of the invention.

What isclaimed is: 1;. .In a welding gun, a pair. of spaced supports, guide rods extending between supports, a cylinder. mounted on one of .said supportshavingantaxis parallel with said rods, electrode carrying members slidably arranged on said guide rods, a pair; of pistons in said cylinder, and means, for connecting said pistons to said members to, provide forrelative movement therebetween upon relative movement between said pistons.

2. In a welding gun, a pair of spaced supports, parallel guide rods extending between supports, a cylinder mounted on one of said supports, having an axis parallel with said rods, electrode carrying members slidably arranged on said guide rods, a pair of pistons in said cylinder, a sleeve connecting one of said pistons with one of. said members, and a piston rod extending thru said sleeve and said one of saidpistons and connected to the other piston and other member.

I 3. In a welding gun, a pair of spaced supports,

parallel guide rods extending between supports,

a cylindermounted on one of said supports, having an axis parallel with said rods; electrode carrying members slidably arranged on said guide rods, a pair of pistons in said cylinder, a sleeve connecting one of said pistons with one of said members and a piston rod extending thrusaid sleeve and said one ofsaid pistons and connected to the other piston and other membenmeans for introducingfluid pressure between the'pistons, to move the members toward one another and .-r.esilierit means threaded upon the guide rods between the blocks to separate the members.

'4. Ina welding gun, a pair of spaced supports, parallel guide rods .extending'between supports, a cylinder. mounted on one of said supports, having. an axis parallel with said rods, electrode carrying m mb r dab a an ed q q id 041 pair of pistons in said cylinder, a sleeve connecting one of said pistons with one of said members and a piston rod extending thru said sleeve and said one of said pistons and connected to the other piston and other member, means on said sleeve for engaging the member having the cylinder from one side to limit the movement of the sleeve in one direction.

5. In a welding gun, a pair of spaced supports, parallel guide rods extending between supports, a cylinder mounted on one of said supports, having an axis parallel with said rods, electrode carrying members slidably arranged on said guide rods, a pair of pistons in said cylinder, a sleeve connecting one of said pistons with one of said members and a piston rod extending thru said sleeve and said one of said pistons and connected to the other piston and other member, said piston rod extending beyond the other side of said other piston and interacting means associated with said extending rod and other side of said cylinder member to limit the movement of the piston rod.

6. In a welding gun, a pair of spaced supports, parallel guide rods extending between supports, a cylinder mounted on one of said supports, having an axis parallel with said rods, electrode carrying members slidably arranged on said guide rods, 2. pair of pistons in said cylinder, a sleeve conneoting, one of said pistons with one of said members and a piston rod extending thru said sleeve and said one of said pistons and connected to the other piston and other member and conduit means for introducing fluid pressure into the space between the pistons, said conduit means comprising a bore thru the piston rod extension and piston rod to an outlet point between the pistons.

7. In a welding gun, a support, a cylinder mounted on said support, plural pistons movable in said cylinder, welding electrodes movable into operative engagement with each other, and piston elements each connecting one of said electrodes to one of said pistons, one of said pistons forming a guide for the piston element of the other piston.

8. In a welding gun, a support, a cylinder mounted on said support, plural pistons movable in said cylinder, welding electrodes movable into operative engagement with each other, and piston elements each connecting one of said electrodes to one of said pistons, one of said pistons being apertured to receive the piston element of the other piston, whereby the electrodes are movable into proximity with each other.

9. In a welding gun, a support, a cylinder mounted on said support, two pistons movably mounted in said cylinder, two welding electrodes, and two piston elements each connecting one of said electrodes to one of said pistons, each piston element extending from the same end of said cylinder.

10. In a welding gun, a support, a cylinder mounted on said support, a piston movably mounted in said cylinder, a piston rod secured to said piston and extending through one end of the cylinder, 2. second piston movably mounted adjacent said first piston and having an aperture therein through which the piston rod extends, a sleeve fastened to said second piston and enclosing said piston rod, and electrodes secured to said piston rod and sleeve.

11. In a welding gun, a support, a cylinder mounted on said support, plural pistons movable in said cylinder, welding electrodes movable into operative engagement with each other, piston elements each connecting one of said electrodes to one of said pistons, each of said piston elements forming a guide for the sliding movement of the other said electrodes for normally separating said electrodes.

WILLIAM A. WEIGHTMAN. 

